Study of $\psi(2S)$ production and cold nuclear matter effects in pPb collisions at $\sqrt{s_{NN}}=5~\mathrm{TeV}$

TL;DR

This paper measures $(2S)$ meson production in proton-lead collisions at 5 TeV, analyzing cold nuclear matter effects and deriving $bar{b}$ cross-sections using LHCb data.

Contribution

It provides the first detailed measurement of $(2S)$ production and cold nuclear matter effects in pPb collisions at 5 TeV, including forward-backward ratios and nuclear modification factors.

Findings

Measured $(2S)$ production cross-sections in pPb collisions.

Determined nuclear modification factors and forward-backward ratios for $(2S)$.

Estimated $bar{b}$ cross-section from $(2S)$ and $J/$ decay data.

Abstract

The production of $\psi(2S)$ mesons is studied in dimuon final states using proton-lead collision data collected by the LHCb detector. The data sample corresponds to an integrated luminosity of $1.6~\mathrm{nb}^{-1}$. The nucleon-nucleon centre-of-mass energy of the proton-lead collisions is $\sqrt{s_{NN}}=5~\mathrm{TeV}$. The measurement is performed using $\psi(2S)$ mesons with transverse momentum less than $14~\mathrm{GeV}/c$ and rapidity $y$ in the ranges $1.5<y<4.0$ and $-5.0<y<-2.5$ in the nucleon-nucleon centre-of-mass system. The forward-backward production ratio and the nuclear modification factor are determined for $\psi(2S)$ mesons. Using the production cross-section results of $\psi(2S)$ and $J/\psi$ mesons from $b$-hadron decays, the $b\bar{b}$ cross-section in pPb collisions at $\sqrt{s_{NN}}=5~\mathrm{TeV}$ is obtained.